1. Field of the Invention
The present invention relates to a server apparatus, a network system, a data transfer method, and a program.
2. Description of the Related Art
For accessing a controlled apparatus in a home from a controller on the Internet, a DDNS (Dynamic Domain Name System), an e-mail system, or the like may be used.
In the DDNS, a controlled apparatus in a home registers an own address in a DDNS server. When the controlled apparatus receives a domain name and a port number that are specified by a controller on the Internet, the controller is allowed to access the controlled apparatus.
As a protocol for realizing a real-time communication, an XMPP (extensible Messaging and Presence Protocol) has been proposed (see, “Extensible Messaging and Presence Protocol (XMPP): Core”, RFC3920, The Internet Engineering Task Force (IETF), October, 2004). One of forms of the real-time communication using the XMPP is an instant messaging (IM) (see, “Extensible Messaging and Presence Protocol (XMPP) Instant Messaging and Presence”, RFC3921, The Internet Engineering Task Force (IETF), October, 2004). In the instant messaging (IM), whether IM clients (members among whom an IM exchange can be made) are online is checked. When the IM clients are online, an online conversation (chat) or a file exchange can be made with the IM clients.
Further, as a protocol for calling data or a service in another computer, an SOAP (Simple Object Access Protocol) has been proposed (see, “SOAP Version 1.2”, W3C Recommendation, World Wide Web Consortium (W3C), June, 2003). In communication using the SOAP, a message in which collateral information called envelope is attached to an XML (extensible Markup Language) document is exchanged using a protocol such as an HTTP (Hyper Text Transfer Protocol). Clients that use a service and a server that provides the service both have a creation/interpretation engine of the SOAP, which makes it possible to call an object between different environments.